Build a practice paper from 514 exam-style questions, each with its mark scheme and example answers. Print it, or answer it on paper and then open the mark schemes. Or browse the questions by topic.
4 questions · 7 marks
Computers manipulate binary patterns.
Convert the binary pattern 1010 0100 to denary.
Award one mark for:
164
Why: Correct: 128 + 32 + 4 = 164 (1).
37
Why: Reads the place values from the wrong end (the left-hand bit as 1), so the value is wrong.
3
Why: Counts the 1s instead of adding their place values.
An operating system manages the users of a computer.
Describe how an operating system checks that a user is allowed to log in.
Award up to two marks for a linked description such as:
Do not award for 'it asks for a password' on its own, without saying what the password is checked against.
A stored list/file of users and passwords with no check of the login details earns one mark only.
Do not accept responses about file management, such as finding or opening the user's files.
The user types in a username and password. The operating system compares these with the details it has stored for that account, and if they match the user is allowed to log in.
Why: Username and password entered (1) which is compared with the account details the operating system has stored (1).
The operating system has a list of all the users and their passwords.
Why: The stored list of users and passwords (1), but no check of the login details against it, so the development mark is not earned (0); the mark scheme states a list alone earns one mark only.
The operating system finds the user's files on the hard drive and opens the last one they saved.
Why: Describes file management, not checking a user's login details; the mark scheme says not to accept responses about file management, so there is no creditworthy point.
A device driver is software that allows the operating system to control a piece of hardware. Device drivers are often written in a low-level programming language.
Describe one reason why a low-level programming language is suitable for writing a device driver.
Award up to two marks for a linked description such as:
Extra detail, such as naming the device the driver controls, is not needed to earn the marks.
Do not accept 'it is closer to machine code' on its own: it must be developed to show how this helps the driver, e.g. it can control the hardware directly.
Do not accept 'it is faster/quicker' with no link to the hardware/device, e.g. the device responds quickly.
Do not accept 'it is easier to learn', 'it is easier to debug' or 'it takes less time to write'.
Low-level instructions can manipulate the hardware and memory directly (1) so the driver can control the specific device it was written for, such as a sound card (1).
Why: Point about direct control of hardware/memory (1) linked to controlling the specific device (1). The named device is extra detail and is not needed.
Low-level instructions can manipulate the hardware directly.
Why: Correct point (1) but no linked development saying how this helps the device driver.
It is closer to machine code so it runs faster than a high-level language.
Why: 'Closer to machine code' is not developed into how this helps the driver, and 'runs faster' is not linked to the hardware/device, so no mark.
Binary patterns can represent numbers.
Convert the denary number 199 to 8-bit binary.
Award one mark for each correct nibble in the correct order:
0 marks if the response is not 8-bit binary.
1100 0111
Why: 199 = 128 + 64 + 4 + 2 + 1: both nibbles are correct (2).
1100 1000
Why: Converts 200 instead (a slip in adding up the place values). The first nibble is correct (1); the second is not.
1110 0011
Why: The bits are written in reverse, smallest place value first. Neither nibble is correct.
Teachers: build a paper, print it with the mark schemes at the end, and sign your school up to set your classes activities on every topic.
Fetch Decode Explain isn't affiliated with or endorsed by Pearson Edexcel.